Micro X-ray computed tomography image-based two-scale homogenisation of ultra high performance fibre reinforced concrete. (15th January 2017)

• Record Type: Journal Article
• Authors: Qsymah, A.; Sharma, R.; Yang, Z.; Margetts, L.; Mummery, P.
• Is Part Of: Construction & building materials. Volume 130(2017)
• Page Start: 230
• Page End: 240
• Publication Date: 2017-01-15
• Subjects: Fibre reinforced concrete -- X-ray computed tomography -- Image-based modelling -- Homogenisation -- Finite element -- Pores; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2016.09.020
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Micro X-ray computed tomography (μXCT) images obtained for UHPFRC with 24.8 μm resolution. A two-scale homogenisation method developed for UHPFRC based on CT images and pore sizes. The homogenised elastic moduli compared satisfactorily with experimental data. The method's capability of optimising fibre orientation and volume fraction demonstrated. Abstract: A two-scale analytical-numerical homogenisation approach is developed to predict effective elastic properties of ultra high performance fibre reinforced concrete considering distribution of pore sizes acquired from 3D micro X-ray computed tomography (μXCT) images of 24.8 μm resolution. In the first scale, the mortar, consisting of sand, cement paste and a large number of small pores (10–600 μm), is homogenised using analytical Mori-Tanaka method with constituents' moduli from micro-indentation. In the second, μXCT images of a 20 mm cube are converted to mesoscale representative volume elements for finite element homogenisation, with fibres and a small number of large pores (⩾600 μm) in the homogenised mortar. The resultant elastic moduli are compared favourably with experimental data. This approach accounts for a large number of pores with a wide size range yet without excessive computational cost. Effects of fibre volume fraction and orientation are investigated, demonstrating the approach's potential to optimise the material's micro-structure for desired properties.